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Posted: 6/16/2009 6:11:45 PM EST
I have a 85 mustang with 5.0 carbureted engine that just wont turn over. we have changed the ignition the coil ect but still nothing. The strange thing is when you crank it it doesn't try to start until you release the key then it acts like it is trying to fireup for a second. it is getting fire from the coil and is throwing spark to the spark plugs.
Link Posted: 6/16/2009 6:14:40 PM EST
Check the timing, make sure the timing chain hasn't jumped a tooth. If it has fuel and spark then the next place to check is the timing.
Link Posted: 6/16/2009 6:14:51 PM EST
So you're saying the starter doesn't turn on when you turn the key all the way, but just turns on briefly when you release the key? If so, then sounds like you have an ignition switch problem or some intermittent wiring on the switch.
Link Posted: 6/16/2009 6:15:49 PM EST
Originally Posted By wheel:
So you're saying the starter doesn't turn on when you turn the key all the way, but just turns on briefly when you release the key? If so, then sounds like you have an ignition switch problem or some intermittent wiring on the switch.
starter turns the hole way but it doesnt act like it is trying to start until you let go of the key.

Link Posted: 6/16/2009 6:17:20 PM EST
I have seen ford ignition modules cause the symptoms you describe.
Link Posted: 6/16/2009 6:20:14 PM EST
[Last Edit: 6/16/2009 6:21:32 PM EST by wheel]
Well, if it's turning over, and you have spark, and assuming your timing isn't completely messed up as the other poster mentioned, the only other question is are you getting proper air/fuel mixture. When you pump the pedal do you see the accelerator pump squirting gas down the carb? Is the choke closed? Have you tried flooring it while cranking, in case it's flooded?
Link Posted: 6/16/2009 6:30:25 PM EST
[Last Edit: 6/16/2009 6:30:39 PM EST by TexRdnec]
Originally Posted By m1awolf:
I have seen ford ignition modules cause the symptoms you describe.


that's no flying shit.............

but i'm thinking is the timing too far advanced?

Link Posted: 6/16/2009 7:03:00 PM EST
Originally Posted By Riply21:
I have a 85 mustang with 5.0 carbureted engine that just wont turn over. we have changed the ignition the coil ect but still nothing. The strange thing is when you crank it it doesn't try to start until you release the key then it acts like it is trying to fireup for a second. it is getting fire from the coil and is throwing spark to the spark plugs.


What do you mean "won't turn over"? When you turn the key to the "start" position (all the way clockwise as far as it will go, against the spring), does the starter crank (spin) the engine? You know, make it go "rur-rur-rur"? If it does, it's turning over, just not starting.

When you're cranking it, do you have spark at the plugs? (take a spare plug, hook it to the plug wire and ground it to the block). Is it a strong spark? Make sure the cap and rotor contacts aren't all corroded away and the inside of the cap is dry. You should hear a "SNAP" when the plug fires. If you do, does it sound like it used to when it cranks, or does it seem to spin over faster or with less resistance (compression) than it used to?

Pull a plug out and see if it's wet with gas. Shouldn't be drenched, but it should be damp.

Does it have an electric fuel pump? If it does, you should be able to faintly hear it start when you turn the key from "Off" to "Run". If it's carbureted, than it should have a mechanical pump, but you never know.

If it sounds normal and you have spark when cranking, have you tried pouring a SMALL amount of gas down the carb throat and see if it fires? (unless you're experienced, pour a little gas down the carb then put the air filter back on.....it'll contain backfires if the timing has jumped). If it tries to fire with gas added, you have a fuel supply issue.

The bottom line is that if you have fuel, spark and reasonable timing, the engine WILL start unless you have some catastrophic internal failure.

You could have a weak spark, flooded condition, no fuel, jumped timing, etc. It's just a process of elimination.
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